OBJECTIVES: Tuberculosis is one of the most prevalent infections in humans. Although culture is the reference for diagnosis, its sensitivity is compromised, especially in paucibacillary samples. Because polymerase chain reaction (PCR) amplifies mycobacterial DNA, it is more sensitive than culture for the diagnosis of Mycobacterium tuberculosis (Mtb). However, its performance can be affected by intrinsic sample inhibitors and by the extraction/detection techniques used. METHODS: We evaluated the influence of preanalytical conditions on Mtb detection in samples of sputum (SPU), bronchoalveolar lavage (BAL), and pleural fluid (PF) using combinations of extraction/detection methods. Respiratory samples were prepared to contain different concentrations of red blood cells and nucleated cells to which increasing amounts of Mtb colonies were inoculated and submitted to PCR. RESULTS: Up to 102 CFU/ml of Mtb were detected in the SPU in all methods, except for the Roche extraction/detection method, regardless of the preanalytical sample condition. In BAL samples, medium and high concentrations of cells and high concentrations of red blood cells contributed to a lower Mtb detection, regardless of the extraction method used. In PF, red blood cells were the variable that most interfered with Mtb detection, with better recovery (102 CFU/ml) observed with the Qiagen/Nanogen combination. CONCLUSION: The choice of Mtb extraction and detection method is of fundamental importance for PCR analytical sensitivity, especially when paucibacillary samples and/or samples containing potential PCR inhibitors are analyzed.

INTRODUCTION: Imipenem-resistant Pseudomonas aeruginosa resulting from metallo-β-lactamases has been reported to be an important cause of nosocomial infection and is a critical therapeutic problem worldwide, especially in the case of bacteremia. OBJECTIVES: To determine the frequency of metallo-β-lactamases among imipenem-resistant Pseudomonas aeruginosa isolates and to compare methods of phenotypic and molecular detection. METHODS: During 2006, 69 imipenem-resistant Pseudomonas aeruginosa samples were isolated from blood and tested for metallo-β-lactamase production using both phenotypic methods. Minimal Inhibitory Concentratrions (MIC) (μg/mL) was determined with commercial microdilution panels. Pulsed Field Gel Electrophoresis (PFGE) was performed among metallo-β-lactamase producers. RESULTS: Of all the blood isolates, 34.5% were found to be imipenem-resistant Pseudomonas aeruginosa. Positive phenotypic tests for metallo-β-lactamases ranged from 28%-77%, and Polymerase Chain Reaction (PCR) were positive in 30% (of note, 81% of those samples were blaSPM-1 and 19% were blaVIM-2). Ethylenediamine tetracetic acid (EDTA) combinations for the detected enzymes had low kappa values; thus, care should be taken when use it as a phenotypic indicator of MBL. Despite a very resistant antibiogram, four isolates demonstrated the worrisome finding of a colistin MIC in the resistant range. PFGE showed a clonal pattern. CONCLUSION: Metallo-β-lactamases among imipenem-resistant Pseudomonas aeruginosa were detected in 30.4% of imipenem-resistant Pseudomonas aeruginosa isolates. This number might have been higher if other genes were included. SPM-1 was the predominant enzyme found. Phenotypic tests with low kappa values could be misleading when testing for metallo-β-lactamases. Polymerase Chain Reaction detection remains the gold standard.

Os primeiros herpes-vírus a serem descritos foram os tipos 1 e 2, cuja denominação é herpes simplex 1 e 2 ou HSV-1 e HSV-2. Estes vírus possuem características biológicas particulares, tais como a capacidade de causar diferentes tipos de doenças, assim como estabelecer infecções latentes ou persistentes por toda a vida dos hospedeiros e de serem reativados causando lesões que podem se localizar no sítio da infecção primária inicial ou próxima a ele. Postula-se que a reativação deste vírus no gânglio geniculado esteja relacionada com a paralisia de Bell. Nesta situação, os vírus, que estariam latentes neste gânglio, sofreriam reativação e replicação difundindo-se pelo nervo facial e seus ramos, dentre eles o nervo corda do tímpano, que ao estimular a secreção salivar possibilitaria a identificação do DNA viral na saliva dos pacientes. Até recentemente, um grande número de pacientes eram diagnosticados como portadores de uma forma desta paralisia, chamada de idiopática ou de paralisia de Bell. Com o advento da técnica de estudo do DNA viral pelo método da reação da polimerase em cadeia (PCR), diversos autores encontraram DNA do vírus herpes simplex tipo I no líquido cefalorraquidiano, na secreção lacrimal, na saliva e nos gânglios geniculados de pacientes com paralisia de Bell. OBJETIVO: observar a prevalência do vírus herpes simplex tipo I pela técnica de PCR, na saliva de pacientes com PFP de Bell, relacionando-a com a evolução clínica destes casos. METODOLOGIA: Avaliamos 38 pacientes portadores de Paralisia Facial Periférica de Bell, que foram submetidos a anamnese, exame médico geral e otorrinolaringológico e coleta de saliva para detecção do DNA viral pela técnica de PCR. O grupo controle correspondeu a 10 adultos normais. RESULTADOS: Obtivemos positividade para o DNA viral em 11 casos dos 38 avaliados, o que corresponde a 29% da amostra. Este resultado foi estatisticamente significante se comparado ao grupo controle, no qual não foi obtido nenhum caso de positividade. CONCLUSÃO: Concluiu-se que a presença do HSV-1 na saliva de pacientes portadores de PFP de Bell indica que a reativação viral pode ser a etiologia desta doença. A detecção do vírus na saliva destes pacientes não influencia o prognóstico da doença.

The first herpes virus to be described was types 1 and 2, whose denomination is herpes simplex 1 and 2 or HSV -1 and HSV -2. These viruses have specific biological characteristics, such as the ability to cause different kinds of diseases, as well as to establish host’s latent or persistent lifetime infections and also of being reactivated, causing lesions that can be located at the same site of the initial primary infection or close to it. It is suggested that this virus reactivation in the geniculate ganglion may be related to Bell’s palsy. In this situation, the viruses that would be latent in this ganglion, would suffer reactivation and replication, then be diffused through the facial nerve and its branches, among them the chorda tympani nerve, which by stimulating salivary secretion would enable the identification of the viral DNA in the patients’ saliva. Until recently, a great number of patients was diagnosed as holders of this kind of paralysis, named idiopathic or Bell’s palsy. With the introduction of the technique studying the viral DNA by Polymerase Chain Reaction (PCR), several authors have found herpes simplex virus type I DNA in the cerebrospinal fluid, in the lachrymal secretion, in the saliva and in the geniculate ganglia of patients with Bell’s palsy. AIM: observe the occurrence of herpes simplex type I virus using PCR technique in the saliva of patients with Bell’s palsy and relating it to the clinical evolution of these cases. METHODOLOGY: We evaluated 38 patients with Bell’s palsy submitted to anamnesis, clinical and ENT examination and saliva sampling for viral DNA detection by PCR technique. The control group was ten normal adults. RESULTS: We found positive viral DNA in 11 cases out of the 38, which corresponded to 29% of the sample. This result was statistically significant if compared to the control group, in which we did not find any positive case. CONCLUSION: The end result was that the presence of HSV -1 in the saliva of patients with Bell’s palsy indicating that the viral reactivation can be the etiology of this disease. The detection of the virus in these patients’ saliva does not influence the disease prognosis.